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Synthetic method of oxadiazon

A synthetic method, the technology of oxadiazone, which is applied in the field of pesticide synthesis technology, can solve the problems of non-industrialization process, polluting the environment, restricting the popularization and use of oxadiazone products, etc.

Active Publication Date: 2014-03-19
HEFEI XINGYU CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the existing industrial production, triphosgene is generally used as a substitute for phosgene and diphosgene. Although the reaction is relatively mild and easy to control, it may still decompose and produce highly toxic phosgene, which poses a safety hazard.
In addition, in the phosgene ring synthesis process, there are inorganic salts that pollute the environment and are difficult to remove due to the treatment of reaction tail gas
Therefore, there are environmental and safety hazards in the phosgene synthesis process, and it is not an ideal industrial process, which restricts the popularization and use of oxadiazone products.

Method used

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  • Synthetic method of oxadiazon

Examples

Experimental program
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Effect test

Embodiment 1

[0028] Embodiment 1: synthetic oxadiazone

[0029] Add 2.0Kmol of 2,4-dichloro-5-isopropoxyphenylhydrazide (100%), 5.0Kmol of dimethyl carbonate, catalyst ( 30% sodium methoxide) 0.036Kmol, after the addition, stir, heat up to reflux, after reflux for 4 hours, take a sample to detect that the residual hydrazide is 0.2%, which is regarded as the end of the reaction, cool to -5°C, crystallize, centrifuge, and dry to obtain Oxadiazone 670.9kg, 0.45%, was regarded as the end point of the reaction, cooled to -6°C, crystallized, centrifuged, and dried to obtain oxadiazone 663.8kg, which was detected by gas chromatography at the same time. Chloromethane is dissolved, and tetradecane is used as an internal standard, and a certain chromatographic peak retention time in the resulting product solution ( figure 2 ) and the retention time of oxadiazone chromatographic peak in oxadiazone standard solution ( figure 1 ), the relative difference is within 1.5%, and the chromatographic peak ...

Embodiment 2

[0031] Embodiment 2: synthetic oxadiazone

[0032] Add 2,4-dichloro-5-isopropoxyphenylhydrazide 2.0Kmol (100%), dimethyl carbonate 4.5Kmol, catalyst ( 30% sodium methoxide) 0.05Kmol, after the addition, stir, heat up to reflux, after 4h of reflux reaction, take a sample to detect that the hydrazide residue is 0.22%, which is regarded as the end of the reaction, cool to -5°C, crystallize, centrifuge, and dry to obtain Oxadiazone 667.3kg, 0.45%, was regarded as the end point of the reaction, cooled to -6°C, crystallized, centrifuged, and dried to obtain oxadiazone 663.8kg, which was detected by gas chromatography at the same time. Chloromethane is dissolved, and tetradecane is used as an internal standard, and a certain chromatographic peak retention time in the resulting product solution ( image 3 ) and the retention time of oxadiazone chromatographic peak in oxadiazone standard solution ( figure 1 ), the relative difference was within 1.5%, and the chromatographic peak was ...

Embodiment 3

[0034] Embodiment 3: synthetic oxadiazone

[0035] Add 2.0Kmol of 2,4-dichloro-5-isopropoxyphenylhydrazide (100%), 4.0Kmol of dimethyl carbonate, catalyst ( 30% sodium methoxide) 0.02Kmol, after the addition, stir, heat up to reflux, after 6h of reflux reaction, take a sample to detect 0.42% hydrazide residue, which is regarded as the end of the reaction, cool to -3°C, crystallize, centrifuge, and dry to obtain Oxadiazone 640.7kg, 0.45%, was regarded as the end point of the reaction, cooled to -6°C, crystallized, centrifuged, and dried to obtain oxadiazone 663.8kg, which was detected by gas chromatography at the same time. Chloromethane is dissolved, and tetradecane is used as an internal standard, and a certain chromatographic peak retention time in the resulting product solution ( Figure 4 ) and the retention time ( figure 1 ), the relative difference was within 1.5%, and the chromatographic peak was identified as oxadiazone. The internal standard method detected oxadiazo...

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Abstract

The invention relates to the field of a pesticide synthetic process and discloses a synthetic method of oxadiazon. The synthetic method is used for synthesizing the oxadiazon by carrying out a cyclization reaction on 2,4-dichloro isopropoxy benzhydrazide and dimethyl carbonate under catalysis of sodium alcoholate. The synthetic method disclosed by the invention is carried out in the presence of catalytic amount of the sodium alcoholate by taking the dimethyl carbonate as a carbonylation ring-closing reagent; the dimethyl carbonate is not only taken as a reactant, but also taken as a reaction solvent; a reaction byproduct only has methanol, application of highly-toxic and dangerous chemical substances is avoided, and highly-toxic phosgene is not generated by decomposition, so that no pollution is caused to an environment, and therefore, the synthetic method is safe and environment-friendly, and defects of the conventional process are overcome.

Description

technical field [0001] The invention relates to the field of pesticide synthesis technology, in particular to a synthesis method of oxadiazone. Background technique [0002] Oxadiazon, also known as oxadiazon, is an organic heterocyclic contact-type selective water and dry dual-purpose pre-emergent herbicide. Oxadiazon is characterized by its broad herbicidal spectrum, high efficiency, low toxicity, It has the advantages of less dosage, low residue, no impact on subsequent crops, good ecological benefits, and convenient use, and is very popular among users. At present, the industrial production of oxadiazone mostly uses 2,4-dichlorophenol as raw material, and undergoes ten steps such as esterification, nitration, hydrolysis, etherification, reduction, diazotization, reduction, neutralization, acylation, and cyclization. The reaction obtains the technical route of the former drug of oxadiazone. In the key step of the cyclization process, the existing technology uses phosgen...

Claims

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Application Information

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IPC IPC(8): C07D271/113
CPCC07D271/113
Inventor 何普泉王兰兰
Owner HEFEI XINGYU CHEM
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